DE10123377A1 - Reading data stored on data tape involves reading out parameters describing structure of label depending on data tape type, identifying , reading out label using parameter describing label - Google Patents

Abstract

The method involves entering the data tape type into the reader, reading out parameters describing the structure of the label depending on the data tape type, identifying and reading out the label using the parameter describing the label, reading out the useful data using the information in the label and outputting the useful data. Independent claims are also included for (1) a computer program; and (2) a reader.

Description

The invention relates to a method for reading on egg a data band of stored data by means of a reader direction, whereby on the data band useful data and format data are recorded, and a reading device.

User data is the data that a user of a database which is stored on the data tape and from the data tape again can read. Format data is in addition to the user data data stored on the data tape, that of the structure serving and formatting the user data so that the User data when reading by means of a reading device find and can be read by the reading device.

There are different types of data tapes essentially through the respective data structure below divorce.

Such data band types are, for example: American Natio nal Standards Institute (ANSI), IBM OS / 360, IBM BOS / 360, IBM DOS / 360, GRASP, IBM DOS / 360, POWER II; IBM POWER / VS, IBM POWER / VSE, UNIVAC Series 70 (US 70), Medium Burroughs, Large Burroughs, Honeywell, UNIVAC SDR, IBM OS Writer, NCR, DEC PDP-11, ICL 2900 VME / B.

These types of data bands are in Xerox Laser Printing Systems- Tape Formats Manual, RANK XEROX, Publication 700P91799, Fe February 1991, version 3.5.

The format data of these data band types are often called named labels recorded on the data tapes. This La are at the beginning of a data tape and at the beginning the respective file, usually a A number of different labels are provided. The label  usually have a label ID with which the La be designated. The label ID usually follow a set of formatting and organizational data that the Compu operating system used by the user tersystems and the reading device described and out will read.

For example, with the ANSI data band type there is a a series of labels are provided for each data band, by which the first label is called VOL1, which means "Vo lume 1 "stands. There can be further labels with the designation VOLx, where x is an integer from 1 to 9, or a label HDR1, which represents the so-called header of a file poses, follow.

The labels are assigned differently depending on the data band type draws and are structured differently. This has to Consequence that with known computer programs for reading Data usually only stored on a data tape a data band type can be read. Should with a le device multiple data band types are read, so are a separate program section for each band type (= Function). There is therefore a considerable burden may according to a procedure with which different Da tenband types can be read with a reader NEN.

In known methods, such as one in GB 2,285,525 A described methods, data tapes are each because of a single type. In the case of GB 2,285,525 A resulting procedure becomes a special one enables the user data to be read out quickly.

The invention has for its object a method for Reading data stored on a data tape by means of to create a reading device that reads under Different data band types allowed and yet simple  is trained. Furthermore, the invention has the object reasons, a computer program for executing the invention according to the method and to create a reading device.

The invention is based on a method having the features of claim 1, with a computer program according to claim 11 and a reading device according to claim 18 solved. before partial embodiments of the invention are in the Un claims specified.

According to the method according to the invention, the data stored on a data tape are read out by means of a reading device, useful data and format data being recorded on the data tape, and the format data having labels with which the format of the user data is defined, the method comprising the following steps:

• Entering the data band type in the reading device,
• - Reading parameters that determine the structure of the label describe, the parameters depending on the entered data band type are read out,
• - Identify and read the labels using the Label describing parameters,
• - Reading out the user data using the ent in the label held information, and
• - Output of the user data.

According to the invention, the formats of the individual Da tenband types in the form of parameters, according to their Provided the reading process works. The invention The method can thus be used with a single program section (= a single function) that can be implemented on the Accesses parameters.

The inventor succeeded in creating a structure for the parameters to provide with which basically all data band are sufficiently writable. So are after a preferred one  Embodiment of the invention for each type of tape a separate set of parameters is deposited, with each set Parameters a table with all label IDs of the tape type and, due to the structure of the table, the order with which the labels are recorded on the tape can, is defined. By parameterization it is possible to use different types of data tapes with one single procedure to read.

According to a preferred embodiment of the invention the parameters type designations, whereby each label has a Type designation is assigned. With these type designations the labels can be divided into different groups be, the analysis of the labels when identifying of the same by determining the group assignment is facilitated. So labels that should always be provided provided with type designation "always", which is why when processing an error was immediately detected in a sequence of labels can be, if a label of the type "always" is missing. At the Methods of the invention are of different types drawings used. It is even beneficial to have one Type designation "never" to use, which means that a such a label never exists for the respective data tape type can come. This allows Parame with little effort ter of a data band type to another data band type be changed.

The method according to the invention can be in the form of a computer programs are implemented, with a preferred Embodiment of the invention, the computer program in all common classes and special classes is structured where for methods of the special classes the general classes are inherited, and at least one for each data band type special class is provided. This allows in the data-specific methods and special classes Variables are defined, which then apply to the general Class to be inherited. This is when a  new data band types only necessary, a special one To create class and the variables and methods of all general class, unless they are not specified by the spec All classes are replaced, are kept unchanged. Such a program structure allows a quick and simple adaptation of the computer program to different data types.

In the following, the invention is exemplified on the basis of the Drawings explained in more detail. In which show:

Fig. 1 shows an overview of the method in a flow chart,

Fig. 2 diagrammatically identifying label in a river,

Fig. 3, comparing the read labels with instructions,

Fig. 4 shows the extraction of variables in a flow chart,

Fig. 5 Parameters for reading an ANSI data tape,

Fig. 6 Parameters for reading a Honeywell data tape,

Fig. 7 shows schematically a read apparatus,

FIGS. 8a-8d schematically data tapes with it, on plotted data

Fig. 9 shows the structure of a computer program lead to from the process of the invention schematically in a cloud diagram

Fig. 10 shows a detail of the computer program of FIG. 9 schematically shows a class diagram,

Fig. 11-12b sections of the computer program of FIG. 9 in sequence diagrams, and

Fig. 13 shows a printing system schematically in a block diagram.

An overview of the method according to the invention is shown schematically in FIG. 1. The method begins with a step S1. In a step S2, the data tape 17 is inserted into a reading device 18 and the tape type is entered into the reading device 18 . This can be done, for example, by actuating a correspondingly marked key 19 on the reading device 18 . By pressing this key 19 , previously stored parameters are selected which describe the respective belt type. The reading device 18 is controlled by a control device 20 having a CPU and a storage device.

In step S3 it is checked whether the label describing the label Code on the data tape is in ASCII. Is not this the case, this code is converted into ASCII (step S4). Otherwise, the procedure goes directly to the Step S5 in which the labels are identified. This is explained in more detail below. In step S6, ge checks whether the labels could be identified. Is this not the case, the procedure goes on Step S7, with which a corresponding error message is issued is given and then to step S8, with which the Procedure is ended. Could the label identify who the method goes from step S6 to step S9 with which the identified label is read or ex is trawled. This is explained in more detail below.

In step S10 it is checked whether there is a tape end. is if this is the case, a corresponding one is made in step S11 Function carried out. Otherwise, it is checked in step S12 whether there is an end of file. If this is the case, Step S13 executes an end of file function.

Otherwise, it is checked in step S14 whether a file start is present. If this is the case, a Da becomes in step S15 Partial function executed. Otherwise the procedure goes flow to step S8 with which the method is ended. The process steps S11, S13 and S15 go  in each case to step S8, with which the method be will end.

The main difference to known methods lies in step S5, with which the labels are identified. Before this method is explained in detail, examples of the data structures of data tapes of the ANSI type are briefly explained below with reference to FIGS . 8a to 8d.

Fig. 8a shows a data tape with a schematic Dar position of the data structure. Here, a single file A is stored on a single data tape, which is also referred to as a volume. At the beginning of the tape, two labels VOL1 (= volume 1) and HDR1 (= header 1) are recorded. A Tape Mark TM follows these two labels. This is followed by file A. At the end of the file, a tape mark TM, a label EOF1 (1st end of file label) and two further tape marks TM are recorded, which mark the end of the data tape.

In this example, the labels VOL1, HDR1 and EOF1 and the Tape Marks TM the format data and the file A the Payload data. According to the ANSI standard, the data begins on a data tape always with the label VOL1. Then follows the label HDR1, which describes the data describing file A. includes.

Fig. 8b shows an example in which a file A is divided into three data tapes. These data tapes start with the labels VOL1 and HDR1. The labels VOL1 and HDR1 contain information that determines the order of the three bands. After the end of the respective part of file A, the first two tapes have the label EOV1, which means "1st end of volume label". This label marks the end of the area described on the respective tape. The third data tape has the label EOF1 instead of the label EOV1, the end of the area described on the tape coinciding with the end of the file A. The EOF1 label and the two Tape Marks TM indicate that no further data tape follows.

FIG. 8c shows an example in which two files A, B are stored on a data tape. The beginning of the database is marked with the label VOL1. This is followed by the label HDR1, a tape mark TM and the file A. The end of the file A is marked with the label EOF1 and the beginning of the file B with the label HDR1, these labels each being separated from the neighboring data by a tape mark TM are delimited. The end of file B is marked with the label EOF1, where again two tape marks TM are provided.

Fig. 8d shows an example in which the files A, B and C are divided into three data tapes. The data tapes are initially marked with the label VOL1. The beginning of files A, B and C is marked with the label HDR1, whereby this label is also used at the beginning of the continuation of file B. The end of the files is marked by the label EOF1. The end of the area written on a tape is marked with the label EOF1, provided that this end does not coincide with one end of a file, as is the case with file C. Here again the label EOF1 is used.

The examples shown in FIGS . 8a to 8d show that the labels used in a tape type can occur in different orders. In addition, no optional labels are shown in these examples. In principle, it is also possible for the operating system used or the user to save further information on the format and structure of the stored data on a data tape. According to the ANSI standard, this additional information is stored in the VOLx, UVLx, HDRx, EOFx, UTLx, EOVx labels, where "x" stands for an integer, one-digit number or an ASCII character.

The sequence of these labels is predetermined, however, ei Some labels can be used optionally and depending on the loading may be used by the operating system or the user the.

Other ribbon types come from Xerox Laser Printing Systems- Tape Formats Manual, RANK XEROX, Publication 700P91799, Fe February 1991, version 3.5. This document is under Reference Incorporated.

Fig. 5 shows the structure of parameters that describe the ANSI standard and are used in the inventive method for reading bands of the ANSI type. These parameters are divided into three tables, the sequence table TS, the label table TL and the field table TF. A total of five columns are provided in the sequence table TS for different label IDs. In addition to these five columns, two further columns are provided for sequence sequences 1 and 2, each of which refers to a sequence sequence, which are alternatively possible. The lines list possible label sequences for the beginning of the tape, beginning of the file, data, end of file, end of the tape and the end of the tape. Several labels can be specified in each line. The labels VOL1, HDR1, TM, EOF1 and EOV1 are necessary labels that are "always" present. The remaining labels in this table are "optional". The optional labels, when applied to, are always used in the order in which they are shown in a row of this table. For example, the beginning of the tape can be marked by the labels VOL1, VOL2, VOL3, UVL1, UVL2. The label of the beginning of the tape is followed, as indicated in the column Sequence 1, the label of the beginning of the file with HDR1 etc. In the columns Sequence 1 and Sequence 2, two alternatives are given, such as for the data to which the Follow sequence file end or tape end, one of these two sequence sequences can occur alternatively, with sequence sequence 2 only being used if the first label of the sequence does not correspond to predetermined conditions (identification). After the data and the respective tape mark, the sequence of the end of file follows with EOF1 etc., if there is an end of file, regardless of whether this also marks the end of the tape. Only if there is no data end and the recording area has reached the end of the tape, the following sequence of end of tape is provided.

The structure of the individual labels is in the TL table Are defined. For this, columns for the ID length are the first Label, the last label, the length of the label, the type, and provided different fields. The label VOL1 owns for example an ID length of 4 and the values for it The top and last labels are both set to 0 because it is only some kind of label volume 1 there. With the label VOLx be however, the ID length is only 3 and the first label is to 2 and the last label is set to 9 because x is the Can assume values 2 to 9. The UVLx label has again an ID length of 3 and x can be any ASCII character be. The length of the label VOL1 to HDRx is each because 80. As already stated above, the labels are VOL1 and HDR1 necessary labels and are therefore with the type "Always", whereas the label VOLx, UVLx, HDR2, HDRx with the type "optional" (= optional) verse hen are. The labels can also be of a type "never" (= never). This means that the label never occur. This type designation is advantageous if Tables TS, TL, TF for another, new data band type is created by existing tables of a similar Data band types are changed. Here, labels that not be used with the new data type, with the type "never" be provided. This makes it possible with low  Changes to the main content of the tables to keep.

Providing the labels with the type designations "always, "optional" and "never" allows a simply structured Parameterization of the most diverse data band types. The application of the present method is intended to be expanded be such. B. on reading floppy disks, CDs, etc., so it is basically also possible to use other type designations introduce.

In the individual fields (Field ID1 to Field ID5) are the Designations given for the data stored in it are chert.

The fields are again defined in the field table TF niert, this field table for each field ID a column for the preceding name, type, starting position and the length of the field. This is what the field is called with the field ID Serial_No. the serial number over). It is an alphanumeric field with the start posi tion 4 and length 6.

For the process according to the invention, everyone is using it readable tape type stores a set of parameters, each which includes three tables TS, TL and TF.

In step S2, these parameters are read out for the respective belt type. The identification of the label S5 follows in accordance with these parameters. For this purpose, the method shown in FIG. 2 is carried out, which begins with step S16. In step S17 it is checked whether the label has been identified. If this is the case, the process branches to step S18, which ends the identification of the label. Otherwise, the program flow branches to step S19, with which a read label is compared with a label of the sequence table TS, a pointer pointing to the label of the sequence table. This comparison process begins with step S20. In step S21 it is checked whether the reference length of this label ID is 0. If this is the case, it is checked in step S22 whether the length of the label is equal to the reference length. If this is not the case, step S23 is passed, with which it is determined that the label read out does not correspond to the reference label. This comparison method is then ended in step S24. If the label ID length is not equal to 0, the process flow branches in step S21 to step S25. Here it is checked whether the label ID of the read label matches the label ID of the reference label. If this is not the case, the process branches to steps S23 and S24 described above. Otherwise, it is checked in step S26 whether this label is permitted. The Type column in the TL table table is queried, which can include the term "never"("never"). If the reader is never read here, the label is not permitted and the process branches to steps S23 and S24. Otherwise, it is checked in step S27 whether the length of the label read is equal to the length of the reference label. If this is not the case, steps S23, S24 are branched off again, otherwise step S28. In step S28 it is checked whether the label has an area. The presence of an area means that the label has a variable, such as the variable "x" in VOLx, UVLx or HDRx, which can stand for a number or any ASCII character. There is no such area for the VOL1 and HDR1 labels according to the ANSI standard. If such a label was present, the answer to step S28 would be no and the process flow would branch to step S29, with which it is determined that the label read out is the reference label. Is the read label against a label VOL2, VOL3,. , ., UVL2, UVL3,. , ., HDR3,. , ., the answer in step S28 is yes and the process flow branches to step S30 with which it is checked whether the area is an alphanumeric area. If this is the case, the process flow branches to step S31, in which it is checked whether the character specified for the respective variable is an alphanumeric character. If this is not the case, an error message is output with step S32 and the process branches to steps S23, S24. Otherwise, branches are made to steps S29, S24.

Did the query in step S30 show that no alphanu there is a numerical range rich, with which it is checked in step S33 whether the for Variable specified number is the expected number. is the answer is no, so again the sequence of steps S32, S23, S24 referenced. The answer in the query is Step S33 Yes, it is determined in step S29 that the read label corresponds to the reference label and with the process ends at step S24.

The procedure now goes back to step S19 in FIG. 2, which is followed by step S34, with which it is checked whether a label has been found. If this answer is yes, it is checked in step S35 whether the label is allowed (always, optional) and there is no area or whether the label is not allowed (type never) and has an area. When checking whether there is no area, it is checked whether there is basically no area or whether the last option of an area has been reached. If the test in step S35 results in yes, then the method sequence goes to step S36, in which the pointer is set to the next valid label. In step S23, a flag, which is referred to as a flag sequence change, is set if the last label read is the last label of a sequence and two alternative sequences (in Nextsequence1 and in Nestsequence2) are specified in table TS for the last sequence , Setting the flag sequence change means that there is a change from one sequence to another and that two alternatives are available as sequences.

The flag sequence change works with another flag, the Flag alternative, together, the default is not set. Setting the flag alternative becomes un ten explained in more detail. Then the procedure goes like which to step S17.

If the answer to the question in step S35 is no, ge checks whether the label is allowed. If the answer is yes, the process moves to step S17. Returns the Answer No, it is determined in step S38 that the read label is not permitted and the procedural run goes to step S18.

On the other hand, step S34 has shown that there is no label has been found, it is checked in step S39 whether a There is an error. If step S39 results in an error, the error is output in step S40 and the ver driving flow goes to step S18. The result is On the other hand, step S39 that there is no error, so it is checked in step S41 whether the flag sequence change is not set and whether the flag alternative is not set and the read area is not a data segment and the label is "optional" or "never". Is this Flag sequence change is not set, it means that no sequence change with an alternative sequence is present. If the flag alternative is not set, then meaning This means that the pointer does not point to an old label native sequence (column NextSequence2 in TS) shows. If the test gives a yes, the procedure goes on over to step S36 in which the pointer to the next valid label is set.  

If the query in step S41 results in a no, then the Process flow to step S42 in which checked whether the flag sequence change is not set and whether the flag alternative is set and whether the label of the type "always is. If this query gives a yes, it means that the label is a label of an alternative sequence 2 is why the pointer to the first label of the next sequence quenz 2 is set (step S43). In step S43 also set the flag alternative, which indicates that the read label is a label of an alternative sequence quenz 2 is. The process then goes to the step S17 over. On the other hand, the query in step S42 No, it is checked in step S44 whether the flag sequence alternation is not set and whether the flag alternative is not is set and the read area is not a data segment and the label is of the type "always" or whether the flag-Al is set alternatively and the read area is not there is tensegment and the label is of the type "always". results this query is yes, it is determined in step S45 that the label was not found. It will a corresponding error message is generated and the procedure Pass the sequence to step S18. Returns the Ab if, however, in step S44 a no, the procedure goes flow to step S46, in which it is checked whether the code read is a label of sequence 1 and no alternative label of sequence 2 exists and whether the code is a data segment or whether the read out his code is an alternative label of sequence 2 and whether it is a data segment by querying whether that Flag sequence change is not set and whether the flag Al is not set alternatively and the area read out Data segment, or whether the flag alternative is set and the read area is a data segment. results If this query is yes, the process flow goes to Step S18 over. Otherwise, the procedure is closed next to step S47, with which a corresponding  Error message is generated, and then to step S18 about.

With step S18, the process flow returns to the main method shown in FIG. 1, in which, as has been explained above, it is checked whether the label has been identified (step S6) and then the variables from the label in Step S9 can be read out. The procedure for reading the variables from the label is shown in detail in FIG. 4. This process begins with step S48. In step S49 it is checked whether the field to be sent is the last field of the label. If the answer is yes, the readout process according to FIG. 4 is ended in step S50. Otherwise, the content of the field of the label is copied in step S51 and checked in step S52 whether the field is a numerical field. This check is carried out using the Type column of the TF field table. If the result of the query in step S52 is yes, the characters copied from the field are converted into numerical values in step S52. Thereafter, the process goes to step S54. If the query in step S52 has shown that the field is not a numerical field, the process flow goes directly to step S54. The next field is selected in step S54 and the process flow jumps to step S49. Here the process is run through again until it has been determined in step S49 that the last field has been read out.

The data read out in this way are in steps S10, S12 and S14 correspond to those from tables TS, TL and TF read and interpret the parameters read out, so that the user data is correctly read from the data tape that can.

With the method according to the invention, it is possible to read each type of tape for which the tables TS, TL and TF are stored with the appropriate parameters. In FIG. 6, the corresponding tables TS, TL and TF are given for the Honeywell-band type, for example. The structure of the tables is identical to the tables given in FIG. 5. However, the parameters are adapted to the format of the honey well tape type. In principle, these tables can be created for any type of tape, so that the method according to the invention can in principle be used for all types of tape.

The invention is explained below using a cloud diagram ( FIG. 9), a class diagram ( FIG. 10) and sequence diagrams (FIGS . 11, 12a, 12b). The class and sequence diagrams correspond to the Unified Modeling Language, as they are e.g. B. in the "UML-Unified Modeling Language" whether object-oriented modeling for practice, 2nd edition, (ISBN 3-8273-1407-0) is described.

Fig. 9 is a diagram of a specific cloud structural structure of a program for executing the method according to the invention. This program is programmed in C ++.

The clouds W1 (CActionList), W2 (CActionPos) and W3 (CActionRead) represent three commands to the user are available, whereby with CActionList a kind Directory of the data stored on the data tape saved files is created with CActionPos of the devices pointer is set, which means for example with a data tied the data tape at a specific position above the Read head is positioned, and with the command CActionRead the disk is read.

The clouds W1, W2, W3 each represent classes that are in the Diagram associated with a cloud W4 (CAction), being the cloud W4 is an interface or an interface class. An interface class is a completely abstract class, which means that only the name of the respective me method is defined and a description of the input parameters  and the output parameter is specified. When calling one of the three commands becomes one of classes W1, W2, W3 the interface class W4 is inherited, which means that the in the Interfa ceklasse W4 defined method with program code of the classes W1, W2, W3 is implemented.

The interface class W4 (CAction) uses further interfaces Classes W5 (CInput), W7 (CProcess) and W9 (COutput). The Interface classes W5 and W7 are with a buffer class W6 (CBuffer (Input)) and the interface classes W7 (CProcess) and W9 (COutput) are with a buffer class W8 (CBuffer (Output)) coupled. These classes W6 and W8 include hold buffer sections, each with a flag hen with which write and read processes the ent speaking buffer sections are controllable, the Buffer utilities flags are set. This Classes W6 and W8 are in the international patent application PCT / EP 00/12048 (German priority application No. 199 57 594.0) described. This patent application is hereby included in the disclosure of the present application. The interfaces and classes W5 to W9 generate one from In interface W5 up to interface W9 continuous data stream, the data stream being puffed through classes W6, W8 in this way What is finished is that the above program is both in one Single-threadded mode as well as in a multi-threadded Mode can be run. Many operating systems allowed ben only a single-threadded mode. On such Be drive systems, the program according to the invention is executed bar. However, if an operating system has a multi-threaded Mode allowed and a computer with multiple processors Multi-threaded mode is usually used much more efficient and faster. Through the fiction the appropriate structure of this program is therefore an execution possible in both modes, which on the one hand makes it versatile possible opportunities are created and on the other hand a ma ximally efficient processing is ensured.  

Since the interface classes W5, W7 and W9 do not have their own Pro contain sections of the gram, just the methods define themselves, they use other general classes sen W10 (CDevice), W11 (CDriver), W12 (CLabel) and W13 (CData). For example, class W10 contains variables and methods for controlling devices, in particular of Readers for reading data memories, such as Magnetic tape drives, floppy drives or the like. The Interface class W11 contains variables and methods that form an interface to the drivers of the respective devices. The class W12 (CLabel) contains variables and methods for editing labels on data tapes. And the class W13 (CData) contains variables and methods for processing ten of the read data stream, depending on the data system Modifications made depending on the data type become. These general classes are given by spe specific classes W14 to W18 or W19 to W21 or W22 to W32 or W33 to W42 added. The classes W14 to W18 included Variables and methods for controlling special devices, where in these classes are passed on to class W10 and from Interface W5 can be used. The same applies to the spec Classes W19 to W21 that are inherited from class W11 and are used by the interface W5. With the class Sen W19 to W21 the drivers of the loading are adjusted drive systems on this program.

The special classes W22 to W32 are inherited to the general class W12 and used by the interface W7. These classes form the core of the program, with which the different types of data tapes can be analyzed and read. These classes W12, W22-W32 essentially correspond to the method shown in FIGS . 1 to 4.

The special classes W33 to W42 have variables and me methods that, depending on the data band type, spec Make all modifications to the data and the on the  general class W13 to be inherited. This class structure is also used by the interface W7.

The interface class W9 (COutput) uses two classes W43 (CGCI) and W44 (CNoGCI), which contain the data output which are in GCI format or not in GCI format.

The exact structure of this computer program is explained below using the example of the special classes W22 (CLblANSI) and W24 (CLblHoneywell) as well as the general class W12 (CLa bel). Fig. 10 shows a corresponding class diagram in which these three classes W22, W24 and W12 are shown with their variables and with their methods. This diagram also shows subclasses W12a (CLabelSequence), W12b (CLabelData) and W12c (CFieldData). The general class W12 contains general variables and general methods that access the variables and methods of the subclasses. The variables and methods of the subclasses W12a, W12b, W12c cannot be called directly from the interfaces W5, W7 and W9, but are called indirectly by querying and calling the variables and methods of the general class W12 or the special class W22, W24.

The variables and methods of the general class, too can be called base class, become independent used by the respective data type. In the special Classes W22 to W32 contain variables and methods, which are specially designed for the respective data band type are. In the present embodiment, the special classes no variables, just Me methods. These methods of special classes W22, W24 who inherited from the methods of the general class W12, d. H. that the method of the special class the correspon method, d. H. the method with the same name, of the general class W12. In the present version For example, the methods Init,  PositionBeginningOfFile, PositionEndOfFile, General class PositionEndOfVolume and TapeProcess W12 through the methods of the special class W22, if one Band of the type ANSI or by the methods of the special Class W24 will replace if a Honeywell type tape is made is read. In the Init methods of special classes the parameters for the respective belt type are included.

The interaction of the classes is explained in more detail below with the aid of exemplary program sections using the sequence diagrams of FIGS. 11 to 12b.

In Fig. 11 of the sequence run produced is represented by calling the method Init of the special class W22 for data bands of the ANSI type. This call is made in program step S2 of the flow diagram from FIG. 1. This starts a sequence SEQ1 which is assigned to the special class W22. With this sequence the methods Set and SetNext of the subclass W12a (CLabelSequence) are called repeatedly, which describes the variables of this special class. The method Set describes the rows of the table TS with the respective label sequences and the command SetNext describes the information about the next sequence (NextSequence1 or NextSequence2). These commands are repeated as often as necessary until all rows of table TS have been filled.

This is followed by a similar procedure for describing the table TL by means of the commands SetId, this method in the Class CLabelData is included. This will correspond corresponding variables of this class are described. By opening call the SetId method, the parameters of the the first five columns of the TL table. By the Calling the SetVar method will then make the field names like for Install_ID, Serial_No, etc. in the data fields contribute, whereby the assignment of the fields of the table TF to the labels in table TL.  

The methods SetId and SetVar are in the subclass CLa belData included.

With the method set of the subclass CFieldData the Ta Belle TF described line by line.

This sequence diagram shows schematically how by Aufru methods of the init method of the special class W22 of the subclasses called and executed the. The Init method is used to read a be agreed band type necessary parameters in the corresponding corresponding variables written in the tables TS, TL and Represent TF.

FIG. 12a shows a sequence diagram which shows sections of a structure of a computer program which corresponds to the method according to FIGS. 1 and 2. This computer program calls methods of the special class W22 (CLblANSI) and the general class W12 (CLabel). Furthermore, methods of the subclasses W12a (CLabelSequence) and W12b (CLabelData) are called in this program section. Since this call is made by the methods of the special class W22 or the general class W12, this is shown in the sequence diagrams by corresponding arrows pointing to the respective sequence of the subclass.

This program begins with the CheckType (SEQ2) method, which corresponds to step S1 from FIG. 1. With this method, a read string is checked whether it is a label and, if this is the case, which label it represents. With this sequence, a further sequence SEQ3 is started, which corresponds to steps S3 and S4, with which it is checked whether the string is an ASCII code, and if this is not the case, the ASCII code is translated. The sequence SEQ4 is then called by the sequence SEQ2, which corresponds to step S5 and which accesses methods of the special class W12a via a further sequence SEQ5. Here, nRc means the variable “n return code”, in which a logical value is entered as the return value, depending on whether the label has been identified or not. Furthermore, variables nData and nCur rent are used to control the program.

The sequence SEQ4 calls another sequence SEQ6, with which is queried whether the label has been identified is, this programmatically by a negative Ab ask d. H. whether the label has not been identified, is realized. This corresponds to step S17. The Se sequence SEQ6 calls further sequences SEQ7 and these further sequences or methods SEQ8, SEQ9 and SEQ10, some of which call methods of subclasses W12b and W12a. These sequences correspond to steps S19 (SEQ6), S34 (SEQ7), S35 and S36 (SEQ8), S32 and S38 (SEQ9). At the Se sequence SEQ9, the variable nRc is assigned the value -1, which corresponds to an error if in the upstream Query is determined whether the current label of the type is "never".

The query in sequence SEQ10 checks whether there is an area and if this is the case, the variable nRc is set to zero, which means that there is no error. The sequence diagram of FIG. 12b represents a continuation of the sequence diagram of FIG. 12a, which is why the three sequences SEQ2, SEQ4 and SEQ6 are continued and new sequences SEQ11 to SEQ21 are called up from them. This water program section comprises the program flow from step S34 to step S47 and from there back to the method according to FIG. 1 with steps S10 to S15. Here too, the methods of the special class W22 and the general class W12 call methods of the subclasses and corresponding sequences are started.

Due to the structure with special class and general Classes make it possible to make the program easy and quick to adapt to another data band type by single A new special class is added, in which the Methods are included that are specific to the data band type are to be adapted and contain the corresponding parameters. By inheriting special classes to general ones Classes the programming effort is kept very low. The parameterization according to the invention therefore does not allow only using one program for several data bands pen, but allowed in combination with this program structure also a very quick and easy adjustment this program to other data types. in principle it is also possible with the method according to the invention not only data tapes, but also other data carriers or read other input streams.

FIG. 13 shows a high-performance printing system 1 in which various system components can be via a data network 2 , which can be a local area network (LAN) or a larger network (wide area network, WAN). At least one client terminal 3 depends on the network 2 , on which print jobs can be generated. The terminal 3 is a computer known per se (for example a personal computer PC) with a connected screen 3 a.

The print jobs can optionally also be generated on a main computer (main frame) 4 or at least data from the main frame 4 can be inserted into the print job. The main frame 4 of the data center is controlled by a suitable operating system control such as MVS, BS2000 or VSE. Control functions and displays can be carried out on the main frame 4 via the screen 4 a connected to it. On the main computer 4 (main frame) is also a tape reader 5 and a first high-performance printer 6 directly connected to.

A second printer 7 , a print server 8 and an archive server 9 are also connected to the data network 2 . The print server 8 in turn is connected to a second tape reader 10 and a screen 11 . In addition to the connection 11 between the print server 8 and the main data network 2 , the print server 8 is connected via the connection 12 to a second, local network 15 , to which further printers 13 , 14 are connected. The print server 8 and the printer 14 can optionally be connected to a system for the production of archive memories (CD-ROM) 16 who the. However, the archive system 16 mainly depends on the archive server 9 . Additional screens 9 a, 16 a and 14 a are connected to the respective devices 9 , 16 and 14 .

The tape readers 1 , 5 are process-controlled devices which are controlled by a computer program according to FIG. 9. This computer program is stored on a hard disk or in a semiconductor memory in the tape reader and controls the functions of the tape reader by means of a process control including a CPU.

The tape readers 1 , 5 correspond to the reading device shown in FIG. 1.

The invention can be briefly summarized as follows:
The invention relates to a method for reading data stored on egg NEM data tape by means of a reader device.

The invention is characterized in that the data in Dependence on parameters that affect the format of each Describe, read out and to their full data band types Continuity and correctness are checked.  

This makes it possible to have different types of data to read tapes with a single process.  

reference numeral

1

High-performance printing system

2

Data network

3

Client terminal

3

a screen

4

main computer

5

Tape reader

6

High-performance printers

7

printer

8th

print server

9

archive server

9

a screen

10

Tape reader

11

screen

12

connection

13

printer

14

printer

14

a screen

15

network

16

archive system

16

a screen

17

data tape

18

reading device

19

button

20

control device

steps

S1 beginning
S2 Enter the tape type and read out the parameters
S3 query: Is label code ASCI?
S4 Convert the label code into ASCI
S5 Identify label
S6 Query: Has the label been identified?
S7 ERROR !!!
S8 end
S9 Read the fields
S10 query: end of tape?
S11 tape end function
S12 end of file?
S13 End of file function
S14 Query: beginning of file?
S15 File start function
S16 beginning
S17 Query: Has the label been identified?
S18 end
S19 Compare read labels with reference labels
S20 beginning
S21 query: length of label ID = 0?
S22 Query: Length of the label equal to the length of the reference label?
S23 label is not a reference label
S24 end
S25 Query: Is the label ID equal to the label ID of the reference label?
S26 Query: Is the label allowed?
S27 Query: Is the length of the label equal to the length of the reference label?
S28 Does the label have an area?
S29 label is reference label
S30 Query: Is the area an alphanumeric area?
S31 Query: Is there an alphanumeric character?
S32 ERROR !!!
S33 Query: Is the expected number available?
S34 Query: Was the label found?
S35 Query: Is the label allowed and there is no area or is the label not allowed and does it have an area?
S36 Set pointer to the next valid label in the sequence and, if necessary, set flag sequence changes.
S37 Query: Is the label allowed?
S38 No valid label found
S39 query: error?
S40 ERROR !!!
S41 query: Is the flag sequence change not set and is the flag alternative not set and is the read area not a data segment and is the label of the type "optional" or "never"?
S42 query: Is the flag sequence change not set and is the flag alternative set and is the label of the type "always"?
S43 Set pointer to label of an alternative sequence and set flag alternative.
S44 query: If the flag sequence change is not set and the flag alternative is not set and the read area is not a data segment and the label is of the type "always", or the flag age is set natively and the read area is not a data segment and is the label of the type "always"?
S45 ERROR !!!
S46 Query: Is the flag sequence change not set and is the flag alternative not set and is the area read out a data segment, or is the flag alternative set and is the area read out a data segment?
S47 ERROR !!!
S48 beginning
S49 Query: Last field variable read?
S50 end
S51 Copy field content
S52 Query: Is the field content numeric?
S53 Convert characters to numeric value
S54 Next field

Claims (20)

1. A method for reading data stored on a data tape by means of a reading device, useful data and format data being recorded on the data tape, and the format data having labels with which the format of the user data is defined, comprising the following steps:

• Entering the data band type in the reading device,
• Reading out parameters which describe the structure of the label, the parameters being read out as a function of the given data band type,
• Identifying and reading out the labels by means of the parameters describing the labels,
• - Reading out the user data using the information contained in the label, and
• - Output of the user data.

2. The method according to claim 1, characterized, that one set of parameters for each readable tape type is stored, with each set of parameters the label ei describes the type of tape. 3. The method according to claim 2, characterized, that each set of parameters has a table in which La bel IDs of the respective band type are stored, where through the structure of the table the orders with which wel the labels can be recorded on the tape, de is finished. 4. The method according to claim 2 or 3, characterized, that each set of parameters has a table in which the Format of all labels of the respective band type is defined. 5. The method according to any one of claims 2 to 4,  characterized, that each set of parameters has a table in which data fields contained in the label are defined. 6. The method according to any one of claims 1 to 6, characterized, that the parameters include type designations, each Label is assigned a type designation. 7. The method according to claim 6, characterized, that a type designation ("always") is used that follows indicates that the corresponding label is always in a sequence must be contained by labels. 8. The method according to claim 6 or 7, characterized, that a type designation ("optional") is used that indicates that the corresponding label is in a sequence of Labels can be included. 9. The method according to any one of claims 6 to 8, characterized, that a type designation is used that indicates that the corresponding label never in a sequence of labels may be included. 10. The method according to any one of claims 1 to 9, characterized, that when identifying and reading out the labels they their correctness are checked and when they are found error that is output. 11. Computer program, characterized, that it is to carry out the method according to one of the claims che 1 to 10 is formed.   12. Computer program according to claim 11, characterized, that the computer program in general classes (W10, W12, W13) and special classes (W14-W18, W22-W32, W33- W42) is structured using the methods of special Classes are inherited from general classes, and for each the data band type at least one special class (W22- W32) is provided. 13. Computer program according to claim 12, characterized, that in one of the methods of the special class, the para meters of the respective tape type are included. 14. Computer program according to one of claims 11 to 13, characterized, that the computer program using interface classes in a Input class (W5), processing class (W7) and an output beklasse (W9) are structured, with the input class (W5) and the processing class (W7) or the processing class (W7) and the output class (W9) each have one Buffer class (W6, W8) coupled. 15. Computer program according to claim 14, characterized, that the buffer classes (W6, W8) buffer sections with each have a flag with which Write and read processes of the corresponding buffers cuts are controllable, with the flags of buffer service programs are set. 16. Computer program according to one of claims 11 to 15, characterized, that the computer program in a control device a Reading device for reading data tapes is stored.   17. Computer program according to one of claims 11 to 15, characterized, that the computer program on a machine-readable Da carrier is stored. 18. Reading device for reading data stored on a data tape ( 17 ), useful data and format data being recorded on the data tape, and the format data having labels with which the format of the useful data is defined, the reading device ( 18 ) having a control device ( 20 ), which is designed in such a way that after inserting a data band and entering the data band type in the reading device, parameters are read out as a function of the given data band type, the labels are identified and read out by means of the parameters, and the useful data are contained in those contained in the label Information can be read out and output. 19. Reading device according to claim 18, characterized in that the control device ( 20 ) has a CPU and a storage device and in the storage device a computer program designed to control the reading device is stored according to one of claims 11 to 17. 20. Printing system with at least one printer ( 6 , 7 ), a print server ( 8 ) and a reading device ( 5 , 10 ) for reading data tapes, characterized in that the reading device is designed according to claim 18 or 19.